Patent GB-464251-A (GB)
Title: Improvements in and relating to turbine drives for locomotives and the like
IPC: B61C9/30
Filed: 1936-09-15
Abstract: 464,251. Turbine locomotives. BRITISH THOMSON-HOUSTON CO., Ltd. Sept. 15, 1936, No. 25144. Convention date, Sept. 21, 1935. [Classes 79 (i) and 79 (v)] A locomotive driving arrangement comprises two groups of elastic fluid turbines, one group for use at high locomotive speeds and another group for use at low speeds, each group including a turbine for each axle or group of axles, and the turbines of each group being connected in series. In the construction shown in Fig. 1, a locomotive has four axles 10 .. 13 driven at low speeds by a group of turbines 14, 16, 18, 20 through gears 15, 17, 19, 21, which may be reversing gears. Steam is supplied to the H.P. turbine 14 by a pipe 22, and the turbines are connected in series by pipes 24, 25, 26. At high speeds the locomotive is driven by a second group of turbines 27, 28, 29, 20, driving the axles through the same gears as the first group, the L.P. turbine 20 being common to both groups, though separate L.P. turbines may be provided. Steam is supplied to the H.P. turbine 27 by a pipe 30, and the turbines are connected in series by pipes 32, 33, 34. When one group of turbines is in use steam is prevented from passing from the joint exhaust pipe 26, 34 into the second group by a valve 35 or 36. In order to prevent any turbine from taking more than its share of the load and thus causing the axle driven by that turbine to slip, byepass pipes 37, 38, 39 controlled by valves 41, 42, 43, are provided for the low-speed group and similar pipes 62, 63, 64 and valves 65, 66, 67 for the high-speed group. The L.P. turbine 20 is arranged to take less load in all cases, than the other turbines, so that its axle is not liable to slip. The byepass valves may be hand-controlled, but are preferably operated automatically in accordance with the relative speeds of the axles. The valve 41 is operated by a solenoid 44 energized by two opposed coils 47, 48. The coil 47 is connected by a line 49 to a small generator 50 driven from the axle 10, and the coil 48 is connected by a line 51 to a generator 52 driven by the axle 13. The coils balance each other as long as the axles 10, 13 run at the same speed, but if the axle 10 slips the increased current in line 49 causes the coil 47 to overcome the coil 48 and open the byepass valve 41 against the action of a spring 53. Part of the steam conducted to the H.P. turbine 14 is thus byepassed across to the next turbine 16, and hence the power and speed of turbine 14 are reduced until the speed of axle 10 is reduced to that of axle 13. The byepass valves 42, 43 of turbines 16, 18 and those of the other turbine group are similarly controlled. In the construction shown in Fig. 2, the two H.P. turbines 84, 85 are connected by gearing 86 to two axles 80, 81, and the L.P. turbines 87, 88 drive two axles 82, 83 by gearing 89. The low speed group 84, 87 are connected in series by a pipe 90, and the high-speed group 85, 88 by a pipe 93. Free-wheel clutches 96, 97 are provided between the low-speed turbines 84, 87 and the gearings 86, 89 in order that these turbines may run idle or remain stationary during high-speed operation. Slipping of any axle is prevented by means of valves 98.. 101 for throttling the exhaust from any turbine.